1. Field
The described technology relates generally to an organic light emitting diode display, and more particularly, to an organic light emitting diode display for enhancing film quality of a common electrode.
2. Description of the Related Art
An organic light emitting diode display includes an organic light emitting diode configured by an emission layer, an anode injecting holes to the emission layer, and a cathode injecting electrons to the emission layer. The electrons and the holes are coupled with each other in the emission layer to generate excitons, and light is emitted by energy generated when the excitons fall from an excited state to a ground state.
Any one of the anode and the cathode can be a pixel electrode, and the other one becomes a common electrode. The pixel electrode is formed one by one for each pixel, while the common electrode is formed over the entire display area. An emission layer and a pixel defining layer (or a partition wall), defining an area in which the emission layer is to be formed, are formed between the pixel electrode and the common electrode.
The common electrode may be formed by a spin deposition method. The spin deposition method is a method of disposing a deposition source below the center of the substrate and depositing the common electrode while rotating the substrate. However, as the substrate is enlarged, the deposition of the common electrode is not performed well due to the thickness of the pixel defining layer outside the substrate.
Accordingly, a part of the common electrode is thinly formed or may include a non-deposition area. In this case, a filler between the substrate and an encapsulation substrate or outgas of the filler flows into the emission layer through the non-deposition area to damage the emission layer. Since the damage region of the emission layer is widely enlarged over time, display quality and reliability of products deteriorate.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.